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Behind the Retina

You can look straight at someone for seven seconds and not see them.

27 milliseconds. That is how much slower your reactions get at the legal limit. Nobody can feel 27 milliseconds, and it is not what kills people.

What goes instead is your ability to notice things at all.

Begin runs a 30 second test first. Nothing here shows a crash. Every number is fitted to published measurements.

This simulation illustrates possible effects associated with alcohol impairment. Individual effects vary substantially, and BAC cannot precisely predict a person's subjective visual or cognitive experience.

Behind the Retina

a simulation of attention under impairment

last checked 0.0s ago
40km/h
lane position

How this works

The car drives itself. Your job is to watch what the driver does and does not notice.

  1. Drag the BAC slider on the left. Nothing else changes: same road, same traffic, same hazards.
  2. Hold space at any moment to see the identical road with a sober driver, then let go.
  3. A hazard comes up every few seconds. What the driver noticed, when, and what a sober driver would have done appears on the right.
  4. The attention overlay appears by itself around each hazard, showing where the driver is looking and what is actually being processed.
  5. Explain: on is on: whenever the driver mishandles something, the simulation freezes and shows you what happened. Turn it off to let it run.